For a Long Term Evolution (LTE) system, interference in the system primarily results from inter-cell same-frequency interference. A general method for lowering inter-cell interference is to obviate interference by using an inter-cell interference coordination method. A general principle thereof is to limit the use of resources in an inter-cell coordination way, where available time and frequency resources are limited or transmission power is limited over specific time and frequency resources. A simple implementation method is to perform static inter-cell interference coordination, as illustrated in FIG. 1, in which there are two schemes:
In the first scheme, the entire system bandwidth is divided into four segments, where only one of three sub-bands A is available to each cell at the edge of adjacent cells, and only sub-band B is available at the center of the cell. It can be seen that at this time the entire system bandwidth can not actually be used by any cell for working, that is, for any cell, there are idle sub-bands in which no signal can be transmitted, but hardware devices of the cell still support the cell to work throughout the system bandwidth (i.e., 3A+B), thus resulting in costs of the hardware devices and useless power consumption.
In the second scheme, the entire system bandwidth is divided into three segments, where only one of three sub-bands A is available to each cell at the edge of adjacent cells, and only the entire system bandwidth is available at the center of the cell. However at this time, transmission power at the center of the cell need be lowered in order to alleviate interference of a user at the center of the cell to another user outside the cell. It can be seen that although at this time the entire frequency band can be used by any cell for working, transmission at full power can not be performed, thus reducing power amplification efficiency.
The foregoing inter-cell interference coordination schemes are applicable only to physical downlink shared channels and physical uplink shared channels, and for broadcast channels, synchronization channels, control channels and other common channels in LTE, since their occupied time and frequency resources are relatively fixed, interference can not be obviated by the simple resource coordination way. Moreover, although the existing inter-cell interference coordination schemes can lower inter-cell interference of shared channels effectively, they can not be applicable to transmission of broadcast, synchronization, control channels and other common channels; and when applied to shared channels, there are problems of wasting hardware resources in a base station and increasing useless power consumption. Furthermore, costs of network deployment are also increased.
In summary, lowering interference in the inter-cell interference coordination schemes at present typically results in a low resource utilization rate of the cell or a limitation on the transmission power, and consequently a waste of hardware resources in the base station and an increase in power consumption.